我在 MySQL 数据库中有三个表bids，offers和matched. 该matched表包含已匹配的出价和出价。有一个事件运行逻辑来进行如下所示的匹配，该事件有效。
CREATE EVENT bid_offer_matching
ON SCHEDULE EVERY 1 SECOND
STARTS CURRENT_TIMESTAMP
DO
INSERT INTO Matched(
consumer_id, /* Bidder */
producer_id, /* Offer */
bid_id, /* bid id */
offer_id, /* offer id */
volume, /* Volume */
price, /* Price */
market_time) /* Market Time */
SELECT
bids.user_id, /* Bidder */
offers.user_id, /* Offer */
bids.bid_id, /* Bid ID */
offers.offer_id, /* Offer ID */
bids.bid_volume, /* Volume */
bids.bid_price, /* Price */
bids.market_time /* Market Time */
FROM
Bids bids
INNER JOIN (
SELECT *, ROW_NUMBER()
OVER (
PARTITION BY
offer_volume /* Partition by the volume in the offer */
ORDER BY
/* Order each partiton by the price low to high, this makes row 1 in each partition the lowest price offer*/
offer_price
)rn /* Get the row number also back */
FROM Offers
) offers
ON
/* Volume must be equal */
bids.bid_volume = offers.offer_volume AND
/*Price must be at least asking price */
bids.bid_price >= offers.offer_volume AND
/* Market time must be same */
bids.market_time >= offers.market_time
WHERE
/* This is important, it matches only the above condition to the lowest offer price resulting in best price for bidder */
offers.rn = 1;
当我在表上创建触发器以删除从and表中matched插入的出价和出价时，就会出现问题。我想删除它们，因为一旦它们匹配就不再需要它们。此触发器的逻辑如下所示。bidsoffers
/*Crete the trigger*/
DELIMITER $$
CREATE TRIGGER match_insert_trigger
AFTER INSERT
ON Matched FOR EACH ROW
BEGIN
/* DELETE THE BID*/
DELETE FROM
Bids
WHERE
bid_id=NEW.bid_id; /* The bid ID is inserted into the matched table to be used as reference, not a foreign key though */
/* DELETE THE OFFER */
DELETE FROM
Offers
WHERE
offer_id=NEW.offer_id; /* The offer ID is inserted into the matched table to be used as reference, not a foreign key though */
END$$
DELIMITER ;
但是，当尝试执行事件以匹配出价和出价时，现在会发生错误
Error Code: 1442. Can't update table 'Bids' in stored function/trigger because it is already used by statement which invoked this stored function/trigger.
我只是Bids在事件中更新表格，match_insert_trigger但投标表格不用于触发任何事情，所以有点不确定这里有什么问题？
编辑
通过在事件中放置删除匹配的出价/出价的逻辑，我已经实现了我需要的功能bid_offer_matching。但是，如果有人知道，我仍然不明白上述错误是如何发生的。
下面是新的事件代码
DELIMITER $$
CREATE EVENT bid_offer_matching
ON SCHEDULE EVERY 1 SECOND
STARTS CURRENT_TIMESTAMP
DO
BEGIN
INSERT INTO Matched(
consumer_id, /* Bidder */
producer_id, /* Offer */
bid_id, /* bid id */
offer_id, /* offer id */
volume, /* Volume */
price, /* Price */
market_time) /* Market Time */
SELECT
bids.user_id, /* Bidder */
offers.user_id, /* Offer */
bids.bid_id, /* Bid ID */
offers.offer_id, /* Offer ID */
bids.bid_volume, /* Volume */
bids.bid_price, /* Price */
bids.market_time /* Market Time */
FROM
Bids bids
INNER JOIN (
SELECT *, ROW_NUMBER()
OVER (
PARTITION BY
offer_volume /* Partition by the volume in the offer */
ORDER BY
/* Order each partiton by the price low to high, this makes row 1 in each partition the lowest price offer*/
offer_price
)rn /* Get the row number also back */
FROM Offers
) offers
ON
/* Volume must be equal */
bids.bid_volume = offers.offer_volume AND
/*Price must be at least asking price */
bids.bid_price >= offers.offer_volume AND
/* Market time must be same */
bids.market_time >= offers.market_time
WHERE
/* This is important, it matches only the above condition to the lowest offer price resulting in best price for bidder */
offers.rn = 1;
/* *****DELETE STATEMENT ***** */
/* DELETE THE OFFERS */
DELETE FROM
Offers
WHERE
offer_id
IN
(SELECT offer_id FROM Matched);
/* DELETE THE BIDS */
DELETE FROM
Bids
WHERE
bid_id
IN
(SELECT bid_id FROM Matched);
END$$
DELIMITER ;